1. Field of the Invention
The present invention relates to a method of bonding an insert material and also to a jig used in this method. More specifically, the present invention relates to a bonding material mounting method in which a bonding insert material can be mounted between joining members (to be bonded together) even in an explosion-proof zone, and the invention also relates to a jig used in this method.
2. Description of the Related Art
As shown in FIG. 14, there is known one conventional method of joining pipes or the like together by diffusion, in which a filler (bonding insert material) a, made of a diffusive alloy, is interposed between pipes P.sub.1 and P.sub.2 to be bonded together, and the two pipes are bonded together by diffusion. For effecting the diffusion bonding using this method, it is necessary to set the filler a between the pipes P.sub.1 and P.sub.2 in such a manner that this filler will not move before these pipes are bonded together. Namely, the filler a must be precisely mounted on the pipes P.sub.1 and P.sub.2. This is important particularly in the case of a so-called horizontal bonding in which the pipes P to be bonded together are disposed horizontally.
If the filler a is bonded by an adhesive to an end surface of one of the pipes P so that the filler can be set between the end surfaces of the pipes P, the adhesive is fluidized by heat, produced during the diffusion bonding. Consequently, the adhesive diffuses into the pipes (base metal) to be bonded together, which invites a possibility that the strength of the bonded joint between the pipes is lowered.
As shown in FIG. 15, there may be proposed a method in which the filler a is fused in local portions (spots) thereof, using an electric spark produced by a touch pen b , and is fixedly secured to the end surface of one of the pipes P. In this case, however, if this operation is effected in an atmosphere of flammable gas, there is a risk that the flammable gas is ignited by the electric spark, thereby causing an explosion. And besides, if the filler a is thus fixedly secured to the pipe by the use of the electric spark, there arises the following problems. Namely, a hole is formed in the filler a by the electric spark. Since the filler is liable to be displaced out of position, the filler can not be precisely fixed to the pipe. Because it is necessary to hold the filler a by an appropriate manner during the electric spark fixing, operation time increases and the efficiency of operation is lowered. If the filler fails to be properly held in position, the filler is displaced out of position, as described above. In FIG. 15, reference character c denotes an earth electrode, and reference character s denotes a power source of touch pen.